Disc drives are digital data storage devices which store and retrieve large amounts of user data in a fast and efficient manner. A housing encloses one or more storage media and associated transducing heads which are used to write and subsequently retrieve the user data for a host device. The heads are typically supported adjacent the disc surfaces by fluidic pressures established by the high speed rotation of the discs.
The data storage device (DSD) market continues to place pressure on the industry for DSD's with higher data throughput performance, i.e., data throughput performance as perceived by the host communicating with the DSD. One technique of improving data throughput performance is to delay the physical act of writing data sent by the host (i.e., write data) to the DSD by caching the write data to a buffer memory, storing the write command associated with the write data in a command queue, and reporting a command complete to the host. However, caching write data exposes the data to potential loss through a malfunction of, or loss of power by the buffer memory. One way of reducing the risk of data loss, without incurring an adverse impact on throughput performance, is to nest execution of write commands between consecutive read commands.
Another way of reducing the risk of data loss is to assure the data residing in the buffer memory is allowed to remain in the buffer memory for not more than a predetermined period of time. However, upon expenditure of the predetermined period of time, a write command associated with the write data is scheduled as the next command for execution and the write data is written to the disc. Often times, because of the predetermined operating constraints of the DSD, the cached write data must be written to the disc regardless of the impact on throughput performance, and throughput performance is disadvantageously impacted.
As such, challenges remain and needs persist for improving data throughput performance and consistency of data throughput performance of a DSD.